In the T21-BCF group, we looked at the expression of genes on chromosome 21, especially those that might predispose to BC or have a positive action against BC occurrence, such as BTG3 (OMIM 605673), TIAM1 (OMIM 600687), ETS2 (OMIM 164740), DYRK1A (OMIM 600855), SIM2 (OMIM 600892), Col18A1 (OMIM 120328), IFNAR1 (OMIM 107450), NRIP1 (OMIM 602490), S100B (OMIM 176990), ERG (OMIM 165080),and RUNX1 (OMIM 151385)6. This evidence concerns the gene TIAM1 and breast cancer.